1. Field of the Invention
This invention relates to a template-like mask and its use to accurately position a metal disc, such as a copper heatsink on a surface to which it is to be welded. The mask limits any lateral movement of the disc with respect to the surface as an ultrasonic welding tip presses and bonds the disc against the surface during the welding process.
2. Description of the Prior Art
Metal plates may be ultrasonically welded to one another by placing them firmly against each other between an ultrasonic welding tip and a stationary surface or anvil and applying ultrasonic energy to the tip. The ultrasonic energy is transmitted to the metal plate workpieces causing them to intermolecularly bond one to another. A major advantage of this process is that conductive metals or metals with dissimilar characteristics such as melting temperatures which may present difficulties in thermal welding are easily bonded. This is important in a process which would, for example, attach a copper heatsink to an aluminum backing. Additionally, as little heat is generated by the process, there is little if any cooling time required between welding and subsequent handling. This characteristic is highly desired for high-volume high-throughput automated processes as no cooling step is required.
A device which would automatically place and accurately position a metal disc against a recipient metal backing followed by the ultrasonic welding of this workpiece would augment the process even further. This invention relates to such a device.